The Earth is called the Blue Planet because approx. 71% of its surface is covered by water: salt and fresh water. However, the water we have access to, which we can use in our daily lives, represents only 1% of global resources.

The sources of salt water on Earth are the seas and oceans. But where does fresh water come from? It has three sources:

• Surface water: water from rivers, lakes and marshes;
• Groundwater
• Water ‘locked up’ in glaciers and ice caps

The water we can use in everyday life is really scarce, it is only 1% of all water resources.

It is important to remember that this small amount is a global resource used by people all over the world. It is therefore important not to waste it and to use it wisely.

How much water do we use?

The infographic below shows how much water each of us uses on average for some of our daily activities. It is worth looking at these figures and thinking about what we can do ourselves to reduce the amount of water we use.

What can we do to save water? The answer is the word RETENTION. But what is it?

One of the ways to act effectively to prevent wastage of water resources is retention. It is the ability to store water in small natural and artificial reservoirs, and sub-soil water in the beds of small rivers and streams, in canals and ditches. Small-scale retention is about simple ways of storing water in the local area, many of which we can do ourselves, in our gardens or local spaces. Small retention allows us to stop or slow down water run-off, while taking care of the development of the natural environment. Examples of small-scale retention that we can put into practice ourselves include:

• ecological puddles;
• levees on drainage ditches;
• rain gardens;
• flower meadows;
• above-ground, backyard cisterns into which rainwater is captured;
• underground reservoirs, at home, into which rainwater is caught.

Water footprint – how much water we actually use each day

The water we use to drink and for our daily activities is not all we consume. Our water footprint tells us how much water we really use. The water footprint represents the sum of the water we use directly and indirectly. Directly, we use water for drinking, washing, laundry or cleaning – we can easily determine the amount because we can see when we use it. Indirectly, we consume virtual water, which also comes from global, depletable freshwater resources. The production of every thing we use, wear, buy and consume requires water, it is this water, used in the production process, that is virtual water.

The water footprint measures the amount of water used to produce each good and service we use and can be calculated for an individual person, community, city, country or humanity as a whole.

The water footprint consists of three components: green, blue and grey:

• The green water footprint indicates the amount of water used derived from precipitation.
• The blue water footprint indicates the amount of water used that is obtained from surface and groundwater resources..
• The grey water footprint indicates the amount of water that is contaminated during the production process.

Water footprint of a cotton T-shirt

In order to more easily understand the concept of water footprint and how water consumption is linked to the production of everyday objects, we will analyse the water footprint of a cotton T-shirt as an example.

The cotton T-shirt is made from cotton fabric. Cotton fabric is made from cotton fibres, which of course must be planted and grown in the fields.

Before the final cotton fabric finds its way into our wardrobes in the form of a T-shirt, it must first go through a series of intermediate processes. At each stage of this process, water is consumed.

How is it going?

1. First, the cotton seeds are processed into fibres. From 1,000 kg of cotton seed we get only 350 kg of fibres.
2. Then the fibres are cleaned and after spinning and weaving we get grey fabric. 1000 kg of fibres yields only 900 kg of grey fabric.
3. The grey fabric is then wet-processed (it is bleached and dyed).
4. After bleaching and dyeing, the fabric ends up as the final printed cotton fabric, which we buy in the shop in the form of, for example, a T-shirt.

The average water footprint of 1 kg of printed cotton fabric is 11 000 litres of water. The water footprint of a cotton T-shirt weighing approximately 250 g is therefore 2 750 litres of water.

What is this amount of water used for?

Most, as much as 45% of the volume of water, is water used for cotton irrigation.

41% is rainwater evaporated from the cotton field during the growing season.

14% is the water needed to dilute the wastewater that results from the application of fertilisers to the fields and the use of chemicals in the textile industry. Of this, as much as 23% is water used in the textile industry in the bleaching, dyeing and printing of cotton fabric.

Globally, 210 billion cubic metres of water are evaporated in the annual production of cotton – an amount of water that would fill Poland’s largest lake, Lake Sniardwy, more than 300 times – and 50 billion cubic metres of water are polluted – an amount of water that would fill Lake Sniardwy more than 75 times.

35 litres of water for a 0.5 litre bottle of the popular drink

Another interesting example is a half-litre bottle of the world’s most popular drink. The amount of water needed to produce it was estimated at 35 litres. How does the water footprint of this bottle break down?

• 28 litres of water – this is the water footprint of the ingredients, i.e. the water used for production and cultivation, mainly the cultivation of sugar beet, which is the source of food sugar, but also for the production of ingredients such as phosphoric acid, caramel, caffeine, C02.
• 7 litres of water – this is the water footprint of the entire supply chain, i.e. the water that was used to produce the PET plastic bottle, cap, bottle sticker, pallet and stretch film used in transport. It is also the water used to produce the energy that powers an industrial plant, the production of office supplies, vehicles, fuel and other items related to the direct operations of a manufacturing company.
• The water that is used as an ingredient in a beverage represents only 0.4 litres.

Our everyday choices change reality

It is important to remember that the water footprint we calculate is the water footprint of the product itself. However, in the case of a T-shirt we buy in a shop or a bottle of Coca-Cola, there is also the amount of water that was used to transport the product to the shop and, in the case of a T-shirt, also to produce the label or packaging. At each stage of production some amount of water is used. It is important for us to remember that saving water does not end with reducing water consumption at home, but at every stage of our consumer choices.

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Try making one!

The attached infographic provides information on how much water we use on average for daily activities such as cleaning, laundry and washing, among others. As a homework assignment, encourage students to look at the values presented and calculate with their household how much water the whole family uses each day. Let this be a prelude to considering how this amount can be reduced.

The project was carried out with the financial support of the Malopolska Region